MOVEONLY: fee checks (Rules 3 and 4) to policy/rbf

1 files changed, 3 insertions, 22 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index b0403bffd2..e1d218e358 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -798,32 +798,13 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
         }
 
         // Check if it's economically rational to mine this transaction rather
-        // than the ones it replaces.
+        // than the ones it replaces. Enforce Rules #3 and #4.
         for (CTxMemPool::txiter it : allConflicting) {
             nConflictingFees += it->GetModifiedFee();
             nConflictingSize += it->GetTxSize();
         }
-
-        // The replacement must pay greater fees than the transactions it
-        // replaces - if we did the bandwidth used by those conflicting
-        // transactions would not be paid for.
-        if (nModifiedFees < nConflictingFees)
-        {
-            return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee",
-                    strprintf("rejecting replacement %s, less fees than conflicting txs; %s < %s",
-                        hash.ToString(), FormatMoney(nModifiedFees), FormatMoney(nConflictingFees)));
-        }
-
-        // Finally in addition to paying more fees than the conflicts the
-        // new transaction must pay for its own bandwidth.
-        CAmount nDeltaFees = nModifiedFees - nConflictingFees;
-        if (nDeltaFees < ::incrementalRelayFee.GetFee(nSize))
-        {
-            return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee",
-                    strprintf("rejecting replacement %s, not enough additional fees to relay; %s < %s",
-                        hash.ToString(),
-                        FormatMoney(nDeltaFees),
-                        FormatMoney(::incrementalRelayFee.GetFee(nSize))));
+        if (const auto err_string{PaysForRBF(nConflictingFees, nModifiedFees, nSize, hash)}) {
+            return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee", *err_string);
         }
     }
     return true;